Research in the life sciences field is based upon the analysis of biological materials and samples, such as DNA, RNA, blood, urine, feces, buccal swabs or samples, bacteria, archaebacteria, viruses, phage, plants, algae, yeast, microorganisms, PCR products, cloned DNA, proteins, enzymes, peptides, prions, eukaryotes (e.g. protoctisca, fungi, plantae and animalia), prokaryotes, cells and tissues, germ cells (e.g. sperm and oocytes), stem cells, vaccines, and of minerals or chemicals. Such samples are typically collected or obtained from appropriate sources and placed into storage and inventory for further processing and analysis. Oftentimes, transportation of samples is required, and attention is given to preserve their integrity, sterility and stability. Biological samples can be transported in a refrigerated environment using ice, dry ice or other freezing facility. However, adequate low temperatures often cannot conveniently be maintained for extended time periods such as those required for transportation within or between countries or continents, particularly where an energy source for the refrigeration device is lacking.
Storage containers or storage vessels for such samples include bottles, tubes, vials, bags, boxes, racks, multi-well dishes and multi-well plates, which are typically sealed by individual screw caps or snap caps, snap or seal closures, lids, adhesive strips or tape, multi-cap strips, or other means for containing such samples. The standard container format for medium to high throughput of sample storage, processing and automation of biological processes is a 96-, 384-, or 1536-well plate or array. The containers and the samples contained therein are stored at various temperatures, for example at ambient temperature or at 4° C. or at temperatures below 0° C., typically at about −20° C. or at −70° C. to −80° C. The samples that are placed and stored in the devices are most frequently contained in liquid medium or a buffer solution, and they require storage at such subzero temperatures (e.g., −20° C. or −70 to −80° C.). In some cases, samples are first dried and then stored at ambient temperature, or at 4° C., at −20° C. or at −70 to −80° C.
For example, presently, nucleic acids are stored in liquid form at low temperatures. For short term storage, nucleic acids can be stored at 4° C. For longterm storage the temperature is generally lowered to −20° C. to −70° C. to prevent degradation of the genetic material, particularly in the case of genomic DNA and RNA. Nucleic acids are also stored at room temperature on solid matrices such as cellulose membranes. Both storage systems are associated with disadvantages. Storage under low temperature requires costly equipment such as cold rooms, freezers, and/or electric generator back-up systems; such equipment can be unreliable in cases of unexpected power outage or may be difficult to use in areas without a ready source of electricity or having unreliable electric systems. The storage of nucleic acids on cellulose fibers also results in a substantial loss of material during the rehydration process, since the nucleic acid stays trapped by, and hence associated with, the cellulose fibers instead of being quantitatively recoverable. Nucleic acid dry storage on cellulose also requires the separation of the cellulose from the biological material, since the cellulose fibers otherwise contaminate the biological samples. The separation of the nucleic acids from cellulose filters requires additional handling, including steps of pipetting, transferring of the samples into new tubes or containers, and centrifugation, all of which can result in reduced recovery yields and increased opportunity for the introduction of unwanted contaminants or exposure to conditions that promote sample degradation, and which are also cost- and labor-intensive.
Proteins are presently handled primarily in liquid stages, in cooled or frozen environments typically ranging from −20° C. to storage in liquid nitrogen. In some exceptions proteins may be freeze-dried, or dried at room temperature, for example, in the presence of trehalose and applied directly to an untreated surface. (Garcia de Castro et al., 2000 Appl. Environ. Microbiol. 66:4142; Manzanera et al., 2002 Appl. Environ. Microbiol. 68:4328) Proteins often degrade and/or lose activity even when stored cooled (4° C.), or frozen (−20° C. or −80° C.). The freeze-thaw stress on proteins reduces bioactivity (e.g., enzymatic activity, specific binding to a cognate ligand, etc.) especially if repeated freeze-thawing of aliquots of a protein sample is required. The consequent loss of protein activity that may be needed for biological assays typically requires the readjustment of the protein concentration in order to obtain comparable assay results, or costly rejection of compromised protein reagents in favor of procuring new lots. The common practice of having multiple users of enzyme reagents stored in a laboratory, especially by different users at different times and employing non-standardized handling procedures, further reduces the reliability of experimental data generated with such reagents. As a result, the half-life of proteins is reduced and expensive reagents have to be replaced frequently, amounting to enormous financial costs to the user. For the supplier of the proteins, high costs are required to maintain an undisrupted frozen supply chain starting with initial cold room work-ups, for shipment, frozen storage of the sample, and frozen transport of the protein from production to the site of use. For example, delays during shipment can result in inactivation of proteins, which then have to be replaced at great cost to the supplier; receipt of inactive product can also result in dissatisfied customers.
Drying of proteins and nucleic acids has yet to be universally adopted by the research scientific, biomedical, biotechnology and other industrial business communities because of the lack of standard established and reliable processes, difficulties with recoveries of functional properties and with quantitative recoveries of biological sample material, variable buffer and solvent compatibilities and tolerances, and other difficulties arising from the demands of handling nucleic acids and proteins. The same problems apply to the handling, storage, and use of other biological materials, such as viruses, phage, bacteria, cells and multicellular organisms. See, e.g., Roberts, 2005 Saline Systems 1:5; Galinski et al., 1985 Eur. J. Biochem. 149:135; Malin et al., 1999 J. Biol. Chem. 274:6920; Mascellani et al., 2007 BMC Biotechnol. 7:82. Disaccharides such as trehalose or lactitol, for example, have been described as additives for dry storage of protein-containing samples (e.g., U.S. Pat. No. 4,891,319; U.S. Pat. No. 5,834,254; U.S. Pat. No. 6,896,894; U.S. Pat. No. 5,876,992; U.S. Pat. No. 5,240,843; WO 90/05182; WO 91/14773) but usefulness of such compounds in the described contexts has been compromised by their serving as energy sources for undesirable microbial contaminants, by their limited stabilizing effects when used as described, by their lack of general applicability across a wide array of biological samples, and by other factors.
The genomic age and the recent deciphering of the human and many other genomes, proteomes, transcriptomes, etc. have led to the industrialization of life sciences research. Millions of biological samples including genes and/or gene products from a multitude of organisms are being analyzed in order to advance scientific knowledge and develop commercial products. The development of high throughput technologies has resulted in a vast pool of information and samples, such that there is an increasing need to store these samples for analysis at a later timepoint. Typically samples that may be tested at later times are stored frozen in freezers at −20° C. to −80° C. However with the rapid expansion of demand and capability for analyzing samples by techniques such as polymerase chain reaction (PCR), nucleic acid sequencing, single nucleotide polymorphism (SNP) analyses and other biochemical and/or molecular biology techniques, the available space for storing these samples is rapidly diminishing. Also, universities and other research institutions, reference and diagnostic laboratories and the like are beginning to recognize that the electricity demands for such frozen storage capabilities are constantly growing. Hence, and as the energy pricing rates rise concomitantly, the long term sustainability of this approach is being questioned. It is apparent that a long term sustainable solution to sample storage is vital to the research and diagnostic communities. Clearly there is a need in the industry for convenient, low-cost, energy efficient and accessible life sciences sample storage and retrieval systems. The present disclosure addresses such needs by providing compositions and methods for stably and recoverably storing biological samples such as DNA, RNA and proteins obtained from various biological sources, under anhydrobiotic conditions at room temperature, and offers other related advantages.